Pump piston



H. W. MILLMINE PUMP PISTON Filed Jan. 12, 1934 Q Q@ =2 N W NIH) l ne grwcmtm Patentefl May 11, 1937 Herbert lve, nestles. Tex. Appllcutlon ten: it, use sesls'l No. "looses My lnveutlon reletes to no plstons encl more purtlculel'ly the of piston which is to be eniploteel tn hlels pressure pumps handling materiel more or less sliruslve.

lt ls on object oi my invention to provide menus tor reenforclnu the pecking materiel which forms the seellne" portlon ol the piston. lln pistons of cl'iurscl'er, ln whlcli there is o rubber locally reenlorcecl or motel plates therein, it has lee-en louncl that the softer ruloloer toworol the enrls of the piston is subject to lileli pressureend tenols lee compressed longitudinally so as to bulge out sells-cent the rder rubber toward the middle of the piston. The piston will be worn utljscent the plece where the rubber ls distended one particles of tlle rubber will Toe molten ofi elone the edge of the herd rubber, end lie ulsplececl so eventuullv the softer rubber ot the llne uoljscent liunler rubber will lie weolreneol w and thei end of the piston will be doubled Elect:

one lerolien on.

ls on olilect oi my invention to reenloroe the solter rubber eoljecent the line where it is more llolole to refuel distention, and thus prevent the uewrloretlon off the piston along this llne.

l conteniplute tlie emploent of strong steel wire woven in such manner us to be flexible snol the some ultl'lln the rubber, porticularlv the llue where. the herd and; soil; rubber unel tllus prevent undue expansion of the meter polnt.

is u olojeot or the lnventlon to provlrle plurslltu oil losers of woven steel wire em in tlre runner soul to overlap the lovers to suclr manner to most efieetivelv prevent the eucesslve enpooslon ol the soft rubber owev trons the outer enzl. ol' the plston.

the lserewltlu l hove illustrated my ntlon upplletl to e reenlorceu type of pump p used tor ooulsle octlng portlculerlv sleep well pumping operutlons.

the lllg. l is u side view portly ln elevation onrl in the central longltuulnel see'tlou oppllcetlon of my lnventlon tllereto.

2 is on vlew partly in sectlon and STIl0W-= the use or my invention. 4

3 is o lorolren sectlon oi reenforclne wire which E contemplete usine l'or reenlorclno me= tcu'lel The plston wlcllcli l have shown is mode up cl u plurollty of saucer-shaped steel plates l and l which not us reenlorclng material for the lston. l lenve sltlown two pairs or these plotes l and l, erruneeoi with the concuve feces oi eeclr pole of plot/es facing toward the ends of the piston. Tue pistes l eeljecent the end oi" the piston ore of smeller external diameter than the plates 2. Sold pistes l have clrcuinfereniiol channels 3 one. t therein into which the rubber forming the body of the piston may be molded. There is also it circumferential channel 5 serving the some purpose. The osljecent sides of the two plates ore adopted to contect so as to space them sport lip sliort stuels or projections ll thereon which will lee best understood lrom Fig. 2. Some of these studs are of lorge design and others marked t of smell design. These studs serve not only to space the plates apart, but also act to anchor the rubber to the plates.

The said. plates l just described furnish reenforcements for the end members 9 of comparslively soft rubber molclerl upon said plates. In

} order to obtain s. close bond between the soft ruloleer anal the plate 1 may enclose sold plate in o costing indicated st '2 of hard rubber to which the soft rubber more reeollly may adhere. Toe memhers have the outer face concaved and extended longitudinally toward the outer margin, and the circumterencesof the encl members are also extended outwardly at u so on to he them oversize to better contact with the wells at the cyl finder and seal therewith.

The ler pistes 2 are slsrly provided with studs 6 engaging the similar studs on the lorwurcl plates sncl hove circumferential channels ll therein into which the rubber moy lee molueu. The lever ol rubber ill on the inner plates ls comperotlvely hustler than the rubber on the lor= were plates 9. ll; furnishes o stronger end support for the ruloloer ol the forward plate snu is oriented to contact closely with the loner well ol the cylinder.

The two pairs ol pistes tllw music up are eelupt= ed to mounted upon the piston rod E2 in the usual manner, one end of the piston being sup poeteol ueuinst s. flange ll on the real one the other cool peering see-inst o conical wosloer l l clumped in position by time nuts it. When tlius ussemlllerl o piston luoving the usual contour is proclucerl. The difficulty with pistons of tl ls churecter is that under the extremely high pressures to which they use subjected, the softer rubher in the cool pistes ll will lee compressed longitucliriolly one; will lie bulged out along the meet= ins surteces lzetween the soft and the hero rubloer inelicetecl e-t in Fig. l. This will cause on cessive expansion recllolly et that point and pieces cl rule or wlll be broken off until the end plates ere weslseueu. Tnev will eventually double back and break off to such an extent that the piston will no longer function.

To prevent this undue expansion of the rubber along this, face, I have reenforced the plates by a special reenforcing layer of woven wire. This wire which I employ is ordinarily called bead wire. It is made up of strands of steel wire ill interwoven as shown in Fig. 3. A band of this woven steel wire will resist radial expansion of the rubber when embedded therein and is found to be a most effective means for reinforcing the piston. As seen in Fig. 1 these bands of woven steel wire are extended around the piston preferably in circumferential bands, although this particular arrangement is not compulsory. I arrange the bands so that their adjacent sides will overlap, the first or outer band l8 being embedded partly in the hard rubber l l and partly in the soft rubber $3. The next band i9 extends only slightly within the hard rubber, and is embedded largely in the soft rubber and this band is of smaller diameter than the band 69. There may be a still further layer or this rubber as indicated at 2@ embedded entirely within the soft rubber.

By arranging these bands to overlap in the manner shown it will be seen that when the excessive pressure is exerted against the end of the piston, the rubber will tend to flow outwardly toward the periphery of the piston. With the band arranged to overlap as shown, this tendency of the rubber to flow will be most effectively resisted.

It will also be noted that this arrangement of the reenforcing bands of woven wire will not materially interfere with the seal of the piston against the cylinder walls. It is sufficiently flexible to allow longitudinal movement of the rub her to a certain extent, but will resist the outward expansion of the rubber at the point where it tends to be injured in use. With reenforcing of this character in a heavy duty pump piston for the purpose described, the piston will last for entrance materially longer periods of time and will still form an efiective seal against the cylinder walls while in use.

Having described my invention, what I claim is:

i. A pump piston comprising a plurality of circular plates of rigid material having axial openings to fit upon a piston rod, a body of rubber enclosing said plates and adapted to seal against a cylinder wall, in combination with bands of flexible woven steel embedded in said body and outside said plates to reenforce said rubber and prevent undue expansion thereof, there being a plurality of said bands ratially spaced and sequentially axially displaced in overlapping relation, those farthest from the end of said piston being largest in diameter.

2. A pump piston adapted to fit upon a piston rod and including two pairs of saucer-shaped plates each pair presenting its concave faces out wardly, the inner plate of each pair being embedded in hard rubber, the outer plate of each pair being embedded in softer rubber, said piston being of circular shape to engage within cylinder, and woven wire reenforcing material embedded in said hard rubber and extending across the line between said hard and said soft rubber to resist excessive outward expansion of said soft rubber along said line in use.

3. A pump piston adapted to fit upon a piston rod and including two pairs of saucer-shaped plates each pair presenting its concave faces outwardly, the inner plate of each pair being embedded in hard rubber, the outer plate of each pair being embedded in softer rubber said piston being of circular shape to engage within a cylinder, and woven wire reenforcing material embedded in said hard and said soft rubber to resist excessive outward expansion of said soft relative to said hard rubber in use, said wire reenforcing material being arranged in overlapping layers, one layer being partly in said hard rubber and partly in said soft rubber.

HERBERT WILLIAlli MILLMINE. 

